Incorporation of frazil ice into a sea ice/ocean model
Nikhil Radia (PhD student), Daniel Feltham, Miguel Angel Morales Maqueda (CASE supervisor oat the National Oceanography Centre)
The model of frazil ice dynamics describes several processes affecting the population of frazil ice crystals (see Figure) and is based on the previous model of Holland & Feltham , which was developed to describe the production and precipitation of frazil crystals in the ocean cavity beneath an ice shelf. We have adapted this model to the upper layers of the ocean, which now includes a treatment of the surface energy balance.
The model has been built in stages, using laboratory and field studies, and the frazil component is coupled to an vertical ocean mixing model with an imposed horizontal advection. The model is compared with estimates of the ocean-air heat flux measured over leads and polynyas. Frazil ice production, heat loss and salt release rates are calculated and related to GCM variables, e.g. sea surface temperature and air temperature, in order to determine a parameterisation of frazil ice production for use in large-scale sea ice and ocean models.
Figure of the most important processes involved in frazil ice formation in the upper layers of the ocean. (After U. Svensson and A. Omstedt. Numerical simulations of frazil ice dynamics in the upper layers of the ocean. Cold Regions Science and Technology, 28(1):2944, 1998.)
Holland, PR and DL Feltham, 2005. Frazil dynamics and precipitation in a water column with depth-dependent supercooling. Journal of Fluid Mechanics, 530, 101-124.